Question

A ray parallel to the principal axis, after refraction through a convex lens, passes through:

Options

• The principal focus on the other side

• The principal focus on the same side

• The optical centre

• The centre of curvature of the first surface

Answer 1

A ray parallel to the principal axis, after refraction through a convex lens, passes through the principal focus on the other side of the lens. This is because a convex lens converges parallel rays at its real focus.